DIY Sewer Mainline Replacement Plan

I have tree roots growing into my clay pipe sewer line. I have had a camera sent down the line showing the root invasion in several of the joints. Since the first backup I have snaked the line yearly to prevent problems but this year the roots beat me to the punch and had a backup after 8 months. The wife says enough and wants the line replaced. The camera showed the roots invading the line underneath my property but not underneath the road before the sewer tap. My city will issue me a permit to work on the section before the right of way so I am going to try this myself rather than drop 8 grand. Here is my plan.

I have gotten the plat for my house and know exactly where the sewer line is located. It is 6-7 feet deep at the house and 4-5 feet at the sidewalk. It is a 37 foot run from the house to the sidewalk. I plan to rent a mini-excavator to dig the trench and hydraulic shoring equipment to shore the sides. I am well aware of the safety issues here. Code requires 6 inches of pea gravel below the pipe and minimum 1/4 inch drop per 1ft run. I plan on using gasketed SDR-35, ASTM 3034 approved pipe which is accepted here by local code. Shielded Fernco couplings, guessing cast iron to plastic at the house and then plastic to clay at the sidewalk. Plan on installing cleanouts at the house and sidewalk.

Questions:
1. What do you recommend using to make a clean straight cut on the clay pipe to accept the Fernco?
2. Any issues to think about when backfilling to avoid affecting the line?
3. Anything else?

ABSOLUTELY a MUST to have a "dig alert" service survey the area. The dangers and liabilities from digging up possible water, gas, phone, electrical...are large. And in most places, the LAW requires the use of dig alert.

Are you aware of how much hand digging will also be involved? How long are you prepared to be without sewer while you work on this?

You will need a full size back hoe for this a, mini will take 3-4 times longer and may not even work...I think they do 6-7' deep but that is it's max depth not the working depth...do you also have a drag box so if the trench colapses they won't be just backfilling and placing a marker on the spot you died....what size bucket are you using...

A mini hoe will not have a bucket wide enought to dig the ditch you need for a 6' to 8' deep sewer. Between that, and the shoring, I assume you will be spending most of that $8,000.00 anyway, assuming that is really what it would cost. I would NEVER use SCR pipe at that depth. It crushes at 4' and has to be replaced.

Thanks for the repsonses. I already called and had the ultilies marked, nothingwithin 12 feet of the trench.

I can get a mini-excavator with an 18 inch bucket that digs to 11 feet or a backhoe with I think a 24 inch bucket that digs to 14 feet, that big enough?. Both are around $250 a day.

The SDR-35 is OK with the city. My neighbor just had his line done, same depth as mine and that's what they used but I could go with the SDR-26 if that is better. Don't know if sch. 40 PVC is approved or not but could check if that is recommended.

I would spend the few extra bucks and use SDR-26 pipe with the SDR-35 fittings. SDR-35 pipe is junk. If you are in the Chicago area, and you are only replacing 40 foot of pipe, I can do the whole job for around 4k.

I have inspectors here that will only allow Sch 40 underground outside is when the water and the sewer are in the same trench or less than 10 feet apart from each other.. Thats when the code states that if the water line and building sewer line are in the same trench the material must be of building drain pipe.

Now if there is a 10 feet separation of the water and sewer, then the sewer pipe must conform to the standards of approved materials for building sewer.

Of course this is Illinois plumbing code which is the states care minimum. Cities, and counties can make it stricter. I had a county inspector had me use ductile iron in the park way for a building sewer.

I will use whatever is the best pipe as long as it is approved by code. So is the consensus sch. 40 over sdr-26?

Back to my first question. What's the best tool to use to make a clean straight cut on the clay pipe? Grinder with a diamond wheel?

Click to expand...

I basically said SDR-26 if there is a 10 foot separation of the water supply and the building sewer. If the water and the sewer are closer than 10 feet then it has to be SCH 40. Check with your local codes first. There are a few towns around here that want cast iron instead of SCH 40.due to their codes stating that they do not allow SCH 40 to be used underground as a building drain.

As to cutting clay pipe the chain snap cutters is the best way to cut clay pipe, as Redwood pointed out. Also the couplings to make the connection from the clay pipe to the plastic pipe should be no-shear couplings.

If SCR is acceptable, then sch. 40 would be a major upgrade and NO inspector should reject it. I have never used SCR, and ALWAYS use sch. 40. But I have replaced flattened SCR sewer lines. Remember, Orangeburg was also an approved material at one time, so just being permitted by the code does not mean it is a "good" material.

Called my water/sewer district today and they will not approve sch. 40 saying that ground movement can fracture the glued joints. I live on the side of a big hill with type B soil. He recommended the sdr-35 but when I asked about sdr-26 he said that would be fine, so I guess I'm stuck with that.

I'm very fond of SCH40 applications but ground movement can easily shatter glued connections underground. I've always felt that 20' sections of SCH40 with minimal deflection and the use of 4-band mission no-hub couplings underground are the best way to go.

Any pipe you can put in your hand and distort the inside diameter of is going to be a problem with the movement of weight created by good ole mother earth.

Just dig a hole in a ground and fill up a drywall bucket and tell me how heavy that bucket is, when full.

A mini hoe will not have a bucket wide enought to dig the ditch you need for a 6' to 8' deep sewer. Between that, and the shoring, I assume you will be spending most of that $8,000.00 anyway, assuming that is really what it would cost. I would NEVER use SCR pipe at that depth. It crushes at 4' and has to be replaced.

Even that would not always be right. For most soil compaction densities SDR 35 can be buried 40 â€“ 50ft and still be below the 7.5% vertical deflection threshold allowed per ASTM D3034.

For the homeownerâ€™s purpose, the 7â€™ depth with no traffic/road load will not be a problem.

Click to expand...

SDR 35, its junk, on paper it should do what it is designed for, but in real life applications I seen it go oval at 10 feet deep. Also seen SDR 35 clean out risers get tore up by cable machines. Most villages around here want SDR 26, due to the above concerns I just posted.

Personally I would never ever install SDR 35, even if it cost me the job in pricing difference.

No. I have changed many SDR sewers 4' deep because they had become oval due to ground pressure. ANd the deep they go the worse they get. I do not know where all those "fractured" joints are coming from because we have been using sch. 40 pipes for the past 50 years, or more, and I can not think of a single sewer that has been dug up and repaired because of a "fractured" joint.

I cut my clay pipe with a recipricating saw and a long diamond blade. If the clay is fractured, I would think the chain snapper would just crush the pipe. I'm not sure I'd trust it on good pipe though either. You know, sometimes the old joints just come apart easily, and if that's the case you should be left with the bell end of the pipe that you may be able to join to.

I've only made spot repairs, but I'll tell you it's tough working down in the hole/trench. In a hole it's like bending at the waste and threading shoelaces in your shoes in the dark while wearing them. You definately want to make certain that the walls are shored up well or cut back enough that it won't collapse. You'll probably want at least 2' down there and that will be tight. What kind of soil do you have?

I think you said 37 feet....that's not too bad. I think mine is 80 feet and I got a rought estimate of like $12K once upon a time.

As far as being without sewer service, that kind of sucks. When I did my last repair I just left the hole open and I took a shower (couple actually) ... water came in one side and flowed out the other side. It was already wet down there and the clay soil other than being slippery didn't go anywhere. I did check the pipe with a light and a mirror to make sure it wasn't obstructed by dirt before I closed it up.

You're going to need a transit or at least a good laser level too for checking your elevations. It helps to have someone checking this while you're digging. You don't want to over excavate it for risk of settlement which could cause bellies where it's been filled.

I don't know about the official backfilling procedure when done, but I've used water to help it settle. Fill some, water it down, walk on it, fill some more, add water, etc. I still always end up with more dirt left over than when I started and I still have no appreciable settling at the surface.

Make sure you get someone to locate the actual pipe for you. The last thing you want is to dig up your yard all over because you can't find the dang pipe!